Smart cards have a thickness of no more than about 1 mm and an embedded chip connected to conductive pads on one of its faces. Data is read into and out of the chip by a reader with contacts that engage the pads. The card is commonly inserted forwardly into a slot of a card reader. If perhaps ten millimeters at the rear of the card projects from the card reader then this facilitates pullout of a card. However, such long projecting portion is undesirable, as a person moving across the projecting card portion may be hurt and/or the card may be damaged. It is desirable that the card reader enable the card to be almost fully inserted and later be ejected by a several (at least five) millimeters for pullout, in a compact reader such as one that can fit in a cell phone, and with tactile feedback assuring a person of full insertion.
In accordance with one embodiment of the present invention, a compact smart card reader is provided, which enables substantially full insertion of a card and later rearward pushout of the card by a plurality of millimeters so the card be grasped and fully pulled out, in a compact and simple reader construction. The reader has a frame with a rear body, the body having a pair of legs projecting forwardly from opposite sides of a rear part of the rear body. The frame also includes a front body with a rearwardly-opening cavity whose opposite sides receive and are fixed to each of the legs. The front body has a middle cavity that opens rearwardly. A carriage is slidably guided in forward and rearward movement between the legs. At least one spring biases the carriage forwardly, and at least a portion of the spring and of the carriage lies in the middle cavity portion of the front body.
The reader has a double click mechanism that latches the carriage in its forward position the first time the card is pushed forward to an overtravel position. The second time that the card is pushed forward, the mechanism releases the card to be moved rearwardly by the spring. The legs form a pair of stops that define the overtravel position. The double click mechanism includes a cam formed by a heart-shaped recess in the carriage, and a cam follower that engages the cam and that is pivotally mounted on the frame. A helical spring that pushes the carriage forwardly, presses against a pivoting part of the cam follower to provide friction against free pivoting, so as to assure better operation of the double click mechanism.
The novel features of the invention are set forth with particularity in the appended claims. The invention will be best understood from the following description when read in conjunction with the accompanying drawings.